// IMVU's public API: who an account is, its tagline (for linking) and whether it's age verified or has Access Pass;
// rooms (for the rooms list); and products (the IMVU products T5 products derive from). The hub calls it rarely
// (linking, age checks, rooms T5DE users enter, uploads) and depends on it for nothing else.

export type ImvuUser = {
  id: number;
  username: string;
  tagline: string;
  ageVerified: boolean;
  accessPass: boolean;
  picture: string | null; // the avatar's picture (https, on *.imvu.com)
};

export type ImvuRoom = {
  instanceId: string; // "<owner>-<n>"
  ownerId: number;
  name: string;
  description: string;
  imageURL: string;
  privacy: string; // "public", ...
  type: string; // "listed", "unlisted", ...
  contentRating: string; // "GA", "AP"
  accessPass: boolean;
  occupancy: number;
  capacity: number;
  expired: boolean;
};

/** An IMVU product's public info, as T5 products derived from it show it. */
export type ImvuProduct = {
  image: string | null; // https, on *.imvu.com
  categories: { id: number; name: string }[]; // outermost first, e.g. Clothing / Clothing for Female / Tops
  gender: string; // "female", "male", or "" (either)
};

export class NoSuchImvuUser extends Error {
  constructor() {
    super("no such IMVU account");
  }
}

export class ImvuUnavailable extends Error {}

// Calls are spaced out so the hub never floods IMVU.
const minInterval = 200;

export class ImvuClient {
  private next = 0;

  constructor(
    readonly base = "https://api.imvu.com",
    private readonly fetchFn: typeof fetch = fetch,
  ) {}

  byUsername(username: string): Promise<ImvuUser> {
    const name = username.trim();
    if (!name || name.length > 64) return Promise.reject(new NoSuchImvuUser());
    return this.get(`/user?username=${encodeURIComponent(name)}`).then(parse);
  }

  byId(id: number): Promise<ImvuUser> {
    return this.get(`/user/user-${id}`).then(parse);
  }

  /** A room by its instance ID ("<owner>-<n>"); undefined if there's no such room. */
  async room(instanceId: string): Promise<ImvuRoom | undefined> {
    if (!/^[0-9]{1,12}-[0-9]{1,12}$/.test(instanceId)) return undefined;
    try {
      return parseRoom(await this.get(`/room/room-${instanceId}`), instanceId);
    } catch (e) {
      if (e instanceof NoSuchImvuUser) return undefined;
      throw e;
    }
  }

  /**
   * An IMVU product's public info; null if IMVU shows no such product publicly (it answers 401 for some, such as
   * Access Pass ones). Throws ImvuUnavailable if IMVU can't be reached.
   */
  async product(id: number): Promise<ImvuProduct | null> {
    if (!Number.isSafeInteger(id) || id <= 0) return null;
    try {
      return parseProduct(await this.get(`/product/product-${id}`, [401, 403]), id);
    } catch (e) {
      if (e instanceof NoSuchImvuUser) return null;
      throw e;
    }
  }

  private async wait() {
    const now = Date.now();
    const at = Math.max(now, this.next);
    this.next = at + minInterval;
    if (at > now) await Bun.sleep(at - now);
  }

  /** GETs an IMVU API path; 404 (and the statuses in `missing`) throw NoSuchImvuUser. */
  private async get(path: string, missing: number[] = []): Promise<unknown> {
    await this.wait();
    let response: Response;
    try {
      response = await this.fetchFn(this.base + path, {
        headers: { "User-Agent": "t5de-hub (https://git.t5de.dev/t5de/t5de-hub)" },
        signal: AbortSignal.timeout(15_000),
      });
    } catch (e) {
      throw new ImvuUnavailable(String(e));
    }
    if (response.status === 404 || missing.includes(response.status)) throw new NoSuchImvuUser();
    if (!response.ok) throw new ImvuUnavailable(`IMVU answered ${response.status}`);
    return response.json();
  }
}

export function parseRoom(answer: unknown, instanceId: string): ImvuRoom | undefined {
  const den = (answer as { denormalized?: Record<string, { data?: Record<string, unknown> }> })?.denormalized ?? {};
  const entry = Object.entries(den).find(([key]) => key.endsWith(`/room/room-${instanceId}`));
  const d = entry?.[1].data;
  if (!d) return undefined;
  const str = (v: unknown) => (typeof v === "string" ? v : "");
  const num = (v: unknown) => (typeof v === "number" && Number.isFinite(v) ? v : 0);
  let image = str(d.image_url);
  if (image.startsWith("//")) image = "https:" + image;
  if (!image.startsWith("https://")) image = "";
  return {
    instanceId,
    ownerId: num(d.customers_id) || Number(instanceId.split("-")[0]),
    name: str(d.name).slice(0, 200),
    description: str(d.description).slice(0, 2000),
    imageURL: image,
    privacy: str(d.privacy),
    type: str(d.type),
    contentRating: str(d.content_rating),
    accessPass: d.is_ap === true,
    occupancy: num(d.occupancy),
    capacity: num(d.capacity),
    expired: d.is_expired === true,
  };
}

/** Whether an image address is one of IMVU's (https, on imvu.com or a subdomain). */
export function imvuImage(v: unknown): string | null {
  if (typeof v !== "string" || v.length > 1000) return null;
  let url: URL;
  try {
    url = new URL(v.startsWith("//") ? "https:" + v : v);
  } catch {
    return null;
  }
  if (url.protocol !== "https:" || url.username || url.password || url.port) return null;
  if (url.hostname !== "imvu.com" && !url.hostname.endsWith(".imvu.com")) return null;
  return url.href;
}

export function parseProduct(answer: unknown, id: number): ImvuProduct | null {
  const den = (answer as { denormalized?: Record<string, { data?: Record<string, unknown> }> })?.denormalized ?? {};
  const entry = Object.entries(den).find(([key]) => key.endsWith(`/product/product-${id}`));
  const d = entry?.[1].data;
  if (!d) return null;
  const path = Array.isArray(d.category_path) ? d.category_path : [];
  const categories = path.slice(0, 10).flatMap((c: unknown) => {
    const { id, name } = (c ?? {}) as { id?: unknown; name?: unknown };
    const n = Number(id);
    if (!Number.isSafeInteger(n) || n <= 0 || typeof name !== "string" || !name.trim()) return [];
    return [{ id: n, name: name.trim().slice(0, 100) }];
  });
  const gender = d.gender === "female" || d.gender === "male" ? d.gender : "";
  return { image: imvuImage(d.product_image), categories, gender };
}

// IMVU's "denormalized" answers: the user is the one /user/user-<id> entry.
export function parse(answer: unknown): ImvuUser {
  const den = (answer as { denormalized?: Record<string, { data?: Record<string, unknown> }> })?.denormalized ?? {};
  const users = Object.entries(den).filter(([key]) => key.includes("/user/user-"));
  if (users.length !== 1) throw new NoSuchImvuUser();
  const data = users[0]![1].data ?? {};
  const id = Number(data.legacy_cid);
  const username = typeof data.username === "string" ? data.username : "";
  if (!Number.isSafeInteger(id) || id <= 0 || !username) throw new NoSuchImvuUser();
  return {
    id,
    username,
    tagline: typeof data.tagline === "string" ? data.tagline : "",
    ageVerified: data.is_ageverified === true,
    accessPass: data.is_ap === true,
    picture: imvuImage(data.thumbnail_url),
  };
}